Interesting. Please check cloud GUI for domain configuration. Do you have all fields filled there?
Try to disable CloudFlare for test purposes.
Edit: happy to see it fixed
Hello! Please help me fix this error, when I try create new user in ACP or try accept user registration, i have this "Cannot read property 'toLowerCase' of undefined".
Are there any errors in your nodebb logs?
A good starting point would be to disable all third-party plugins and see if that resolves the issue.